Location and source mechanism of sound signals at Gakkel ridge, Arctic Ocean: Submarine Strombolian activity in the 1999–2001 volcanic episode

Abstract

Gakkel ridge is the slowest spreading mid‐ocean ridge with full spreading rates <10 mm/yr. In 1999, a teleseismic earthquake swarm signaled the onset of an eruptive episode at 85°E. The Arctic Mid‐Ocean Ridge expedition in 2001 detected a hydrothermal event plume and explosive seismoacoustic signals. In 2007, the Arctic Gakkel Vents Expedition found direct evidence for recent submarine explosive activity on the seafloor at ∼4000 m. The newest data motivated a reassessment of the seismoacoustic events of 2001. We undertake 2‐D finite difference wavefield modeling to relocate the source of the signals and investigate the possible source mechanism; the explosion sounds likely result from submarine Strombolian eruptions with bursting gas bubbles rising from a magma reservoir along a major fault at the southern rift valley wall.